1. Field of the Invention
The present invention relates generally to a digital multimedia broadcasting (DMB) receiving terminal, and in particular, to an apparatus and method for changing a DMB channel according to a user's key input data, wherein the channel is not a transmission channel for carrying DMB data but a broadcasting channel for outputting DMB content in a DMB receiving terminal.
2. Description of the Related Art
In general, DMB is a broadcasting service for providing high image and sound quality, and an improved service to users by replacing conventional analog broadcasting. The recent development of DMB technology and improvements in mobile communication technology have caused an increasing interest in DMB service for viewing DMB programming even when in motion. Accordingly, a DMB program can be received using a mobile communication terminal in which is installed an omni-directional DMB receiving antenna. DMB can be classified into satellite DMB (S-DMB) in which a broadcasting signal output from a DMB station is transmitted to a satellite for relaying, and is broadcasted from the satellite to the ground, and terrestrial DMB (T-DMB) in which a broadcasting signal is broadcasted from a ground DMB station in a similar manner to conventional radio broadcasting.
A mobile communication terminal, which can receive and reproduce a DMB signal, includes a DMB signal receiving unit for receiving the DMB signal, extracting DMB data according to a channel set by a user, decoding the extracted DMB data, and outputting the decoded DMB data. The DMB signal receiving unit confirms channel information of a channel selected or pre-set by the user and receives DMB data according to the channel information. The channel information may be Packet Elementary Stream Packet Identification (PES PID) of the DMB data according to the channel or a DMB frequency according to the channel.
The DMB signal-receiving unit also extracts audio/video data or information data by parsing the received DMB data, demultiplexes the extracted data, and outputs the demultiplexed data to a controller of the mobile communication terminal. The controller of the mobile communication terminal decodes the input audio/video data or information data using an equipped DMB module and outputs a DMB program by outputting the decoded audio data and video/information data to an amplifier and a display unit.
FIG. 1 is a block diagram of a conventional DMB receiving terminal.
Referring to FIG. 1, the conventional DMB receiving terminal includes a DMB signal receiving unit 116, an amplifier 114, a display unit 106, and a key input unit 104, which are connected to a controller 100. If a key is pressed by a user, the controller 100 sets a channel according to the pressed key in the DMB signal receiving unit 116. The DMB signal-receiving unit 116 receives DMB data of the channel according to the pressed key. The DMB signal-receiving unit 116 also parses and demultiplexes converted DMB data and outputs the demultiplexed data to the controller 100. The controller 100 decodes the input data and outputs the decoded data to the amplifier 114 and the display unit 106.
Thus, if the user changes the channel, the conventional DMB receiving terminal should perform several procedures. That is, reception of DMB data from a currently set channel must stop, in order to change a channel in the conventional DMB receiving terminal. If a new channel is set without stopping reception of DMB data in the DMB signal receiving unit 116, video and audio data is input to the controller 100 through two channels, causing a problem in the integrity of DMB data. Thus, when a channel is changed in the conventional DMB receiving terminal, the controller 100 stops receiving DMB data by outputting a reception stop signal to the DMB signal receiving unit 116 before a new channel is set. After the channel is changed, the controller 100 controls the DMB signal receiving unit 116 to receive DMB data corresponding to the new channel.
FIG. 2 is a flowchart illustrating a method for the controller 100 of the conventional DMB receiving terminal of FIG. 1 to change a channel according to a key input of the user.
Referring to FIG. 2, if power of the conventional DMB receiving terminal is turned on, the controller 100 outputs a DMB program corresponding to DMB data input through a currently set channel in step 200. The controller 100 determines in step 202 whether a user changes the channel. If it is determined in step 202 that the user has changed the channel, the controller 100 outputs a DMB data reception stop signal to the DMB signal receiving unit 116 in step 204 so that the DMB signal receiving unit 116 stops receiving the DMB data.
The controller 100 temporarily stops interfacing with the DMB signal-receiving unit 116 in step 206. In step 208 the controller 100 deletes a DMB task, which has been created using the DMB data input through the existing channel. Herein, the DMB task is an inner processing to output a DMB program corresponding to input DMB data.
The controller 100 sets a new channel according to a key input of the user into the DMB signal receiving unit 116, creates a message for notifying of a channel change, and outputs the created message to the display unit 106 in step 210. The controller 100 creates a new DMB task for outputting a DMB program corresponding to DMB data to be received through the newly set channel in step 212. The controller 100 restarts interfacing with the DMB signal-receiving unit 116 in step 214. The controller 100 outputs a DMB data reception restart signal to the DMB signal-receiving unit 116 in step 216 so that the DMB signal-receiving unit 116 restarts receiving the DMB data. In this case, the DMB signal-receiving unit 116 receives the DMB data through the newly set channel, and the controller 100 outputs a DMB program of the newly set channel using the newly created DMB task.
Thus, whenever the user changes a channel in the conventional DMB receiving terminal, a process of stopping and restarting reception of DMB data in the DMB signal receiving unit 116 must be performed. In this case, time is required for the DMB signal receiving unit 116 to select a new channel and receive DMB data through the new channel, for setting the DMB signal receiving unit 116 not to receive DMB data, and for setting the DMB signal receiving unit 116 to receive DMB data again. Thus, it is necessary to reduce the time that is spent by changing a channel in the conventional DMB receiving terminal.